We say malware, because it includes all manner of bad software that can infect your computer.

How did it get there?

You ask: How did I get this virus?

My usual answer: I would have to have been watching every move you made on your computer, to identify the exact moment when YOU CLICKED A LINK OR OPENED AN ATTACHMENT that opened the door for malware.
Or, I can ask you this question, which will better serve my needs:
What made you click on that thing?